851c,
NECG can also acquire ERA rings, which are generally a little bit cheaper. NECG can do the work for you, and they seem to be helpful and do good work if a little "pricey". There are a couple different ways to make the conversion to swing mounts, at least one of which can be returned to the original clawmount bases if desired. Generally, the "original claw mounts" are not original to the rifle, they were/are almost always installed "after-market" by someone other than the maker of the rifle. Consequently, I wouldn't worry too much about the originality of the rifle. I think you can have the catalogs translated by your computer if you can't get a translation from the company. Often, on the homepage, there is an option for the desired language. Any translation generated by the computer will not be as understandable as one provided by the company. Good luck.
Mike