Supply Crates - These are freely available and give the best items in the game as they are modable. You pay for them with the in-game currency that you earn called Requisition Points.
Bronze Weapons - Founder Exclusives.
Venerable Pack - Founders and Pre-orders which we extended because Bandai skipped pre-orders. About to be unique and exclusive forever, replaced with 4 faction packs.
Relic pack - Entirely exclusive to Founders and only in giveaways now. This was what was talked about as 5% of the playerbase.
Limited Edition Relics - Entirely exclusive to Founders. They had "Limited Edition Relics" in the name of the store as well as a countdown. This is also what was talked about as 5% of the player base.
Everything else in the Founders Store - Not supposed to be exclusive to founders, the store was just called that as it opened at the same time as the founder program.
If you bought something and didn't get it yet - You should have automatically received the RTC cost of them to spend on something else, and then you'll get the item when it becomes available.
UAT - and something showing up in the store there - If you see something in the store on UAT, it has no relevance to what will be released in game. It's there so you can buy it and test it. Everything has versioning and UAT has a version number which shows in development stuff.
Below is an overview of the weapons from the old Rogue Trader Store. Red crosses mean pending.