I am still looking for a .177 version ... one day one will turn up.
Good luck with restoration. They are fairly easy to work on but take care of the trigger as it is a bit fiddly to put together.
Spring is easy to replace and it is possible to get the piston and rotating breech out without dismantling the trigger but there seems to be a knack to it. There are a few posts around on how to do it .....
Cheers, Phil