My technical issue, yours too?

Just wondering if anyone else is unable to equip certain weapons like the Guillotine Guns and the Eden sword? On top of that I have completed 100 percent of the game and dlc but 4 of the 6 guillotine guns remain unable to be purchased, which doesn't matter really because I couldn't equip it anyway.

Just wanted to ask if this was a common issue or if anyone knew of a workaround similar to the Suger sword suggestion.

Thanks.