I mean, there's always Kyber Pass mystery guns to use as an analogue.
The market for any kind of military goods during the Late Succession Wars must have been flooded with Medium Lasers made by "DefianceHesperusDefianceHesperusDefianceHesperus", covered in random SLDF proofmarks and three-digit serial numbers.
The Periphery might be flooded with that crap just in general.
Even when it needs extensive maintenance and you need to overhaul it pretty much out of the box after buying it... still better than not having anything.
Though Ferengi Rule of Aquisition 294 always applies: A bargain usually isn't.
I thought about using Khyber Pass as an analogy, but while guns are fairly easy to make by hand, high-tech free-electron lasers and multi-ton autoloading 120mm cannons aren't really something you bang out in a backyard workshop. So you do need a considerable industrial footprint to even begin selling components or whole vehicles.
I suppose the best analogy would actually be buying shit on Wish.com. You place an order for ten suspiciously cheap Defiance B3M Medium Lasers and eventually a crate with between nine and eleven De
viance B
ƐM arrives at your depot. The polarity on the contacts is reversed, the cooling fins are gummed together with silicone, the capacitors arrived pre-bulged, the focusing lenses are misaligned, and activating the calibration routine fires the laser (poor Jenkins almost got vaporized when the team found that out), but with a bit of elbow grease, spare parts and copious amounts of cursing you can tweak these lumps of circuits into serviceable Medium Lasers.
You know, that's something that always confuses me. Just what time period is that? The early 31st Century up until the Helm Memory Core? From my limited understanding by the time the 3010's roll around things have mostly stabilized to the point where the worst of the demand has been sated and while things are held together with spit and bailing wire for the most part still there's enough of them to the point militaries are able to start expanding instead of just keeping shit together with bubble gum. No doubt all of the duct tape factories were LosTech given its limitless ability to secure things, so what few reserves were left were saved for only the most important SL-era items.
I mean, you've got the Merlin in 3010, Hatchetman in 3023, and a whole slew of CVs coming off the lines such as the Patton and Rommel, Brutus, Pike, and Hi-Scout all before the Helm Memory Core is found and distributed, and NAIS in 3015 was the harbinger of things to come, and frankly still is since its the most accomplished research university in the whole IS. Heck, the Fourth Succession War in 3028 was the re-introduction of mass warfare into the IS and the end of the lone MechWarrior.
Well, BattleMechs and Fusion Engines were stated as being rare and difficult to manufacture because their factories were deliberately targeted for capture/destruction through the Succession Wars, but apparently
conventional vehicles were still in widespread use. After all, a tank is a much simpler machine to build than a BattleMech, internal combustion engines are a dime a dozen, and as the Soviets were so eager to demonstrate in WWII you can convert heavy vehicle factories into tank factories with a lot less effort than building a whole new factory from the ground up. Even more so if you build said farm equipment factory with quick conversion in mind.
The standard 3025-era weapons were also still very common: the three grades of laser, the PPC, the four sizes of autocannon, the three sizes of SRM launcher and the four sizes of LRM launcher; they are all very rugged, very well-refined pieces of technology. The processes required to manufacture these weapons and their ammo (where applicable) are widely known and, at this point, likely in the Inner Sphere's equivalent of Public Domain. So anyone with the capital and the resources to build a laser factory or a LRM factory could do so, and likely get a few lucrative contracts with planetary or regional governments.