I had the same issue. Check if you have a P90 with an EOT sight attached to it in your inventory, or in any of your stashes. After removing it from the weapon, you should be able to install this addon and load your save no problem, hope this helps.
Comment History
Kayper - - 2 comments @ GUNSLINGER P90 SERIES REPLACER [Update 1.3]
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Kayper - - 2 comments @ GUNSLINGER EXO ANIMATIONS [Update 1]
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This is incredible! Thank you!
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