The "Official MAGA Gear" Trump store on winred.com has items that claim to be made in the USA, including the red hat; however, that store is not an official Trump store. The only official-looking Trump store I could fine was trumpstore.com, which has a lot of items (some of them quite expensive), but with no information on where they were made. (This website is crazy -- you can basically outfit your entire house, pantry, and person with Trump-branded shit at this point.) There's also trumpstoreamerica.com run by some outfit called the Spaulding Group which specializes in conservative-branded merchandise, officialtrump2024store.com which is overpriced Chinesium, and donaldtrumpstore.com which claims to be made in the USA. There's even more sketchy web storefronts. I'm not sure if anyone has ever done a deep dive on this but it may be thread-worthy.
Generally, official campaign items are bought at an official web store or event and are made in the USA with union labor. This used to be true with the Republicans as well as the Democrats. If you want an item, you make a "donation" for the price, which makes it all legal as a campaign donation (like the shooter kid and the ActBlue "donation"). However, all that has changed with Trump, who just appears to sell shit with no pledges on where the money is going. I read yesterday that the superPAC he established to pay his legal bills is almost bankrupt.