Hi Vic,
If you're looking for a broad range, it may be worth searching for previous valuations and transactions on here as that should give you a starting point. Probably worth looking on Gunst*r and Guntr8der as well as sites like Protek and Tim Dyson. You could also trawl through the Kempton photos I have previously linked as I'm sure to have photographed Premiers before. There might be a slight premium for a .177 but I wouldn't have thought this would make much difference to the price as condition is usually more important than calibre.
Kind regards,
John
Currently looking for Baikal Makarov pistols with the following prefixes to the serial number: 98, T01, T09, T21, T22
Prefer boxed or cased but will consider loose examples too.