First let me say, excellent work on your first game. I've just recently begun mucking around with Unreal Engine 4, and think this is probably one of the better shop simulators. I am not sure if anyone has mentioned these issues yet. I looked through many posts, but did not see these issues mentioned in any of the ones I read. OK, now onto the reports!
Platform: Windows x64
Issue 1: When pre-crafting weapons to have on display for quick sells, if the game is saved and restarted, all of the weapons that were pre-crafted before the save are reloaded in pieces. You must then take each piece back to the workbench and reassemble each item.
Steps for reproduction: Assemble weapons and place them anywhere. Save the game, then exit. Re-launch the game and it is loaded with you in your room. Run down to the shop to see the weapons laying in pieces.
Issue 2: When attempting to use the sign out in front of the shop, the edit sign window remains open, as the "Done" button does not appear to work. You can still move around and do everything as normal, however the window remains on the screen until the game is saved and reloaded.
Steps for reproduction: Use the sign out front to name your shop.