I got this 5 Rouble banknote
And for what I can decern it's a Shipov (IPS) and Gusev (IPG) (Issued by the R.S.F.S.R.) signature combination, which isn't listed, not here, not on the banknote museum list this signature combination. Have I found one missing? Or what's the case? I'll add a picture shortly.
Edit: Picture added

Thanks for help in advance :D

