Yes, it certainly is strange. Aperture scale goes all the way to f/50, and if it has been a DIY project, it's been well done, apart from someone painting the back of the lens black, badly, but I'm suspecting someone didn't understand the issues with film thickness problems and was trying to sort that, no doubt also with the tape on the bellows. The is however a record on the internet of a lens like this being sold by Christie's in 2004, I'm wondering if this was our, or someone was doing this mod and selling them. Would love to know what the lens was originally from. Any ideas on bellows repair in the UK?
I will give you a shout about the lens once I've established the state of the camera workings. It came from the estate of a friend that passed away, but I think he was using it.