What is gumi so scum, 1% drop rate with no other alternative. You want to take all my energy pots? You want me to use VISORE for energy? Gumi is scum company
You can't even use it as an upgrade material as +1 requires two, level 1 base guns. Having one at Level 20 doesn't fill the crafting material requirement so you'll have to craft an entirely new one.
It still works, it's just a minimum requirement of level 1. I've leveled plenty on accident to 10 thinking they were +1 and they weren't and still used them.