This will not really answer your question, because I have no first-hand knowledge of the horn. However, here is a link to a brief description from the Woodwind and Brasswind web site. The "G" is for "Gold brass bell." Otherwise, it looks like it might be a standard silver-plated Strad.
http://www.wwbw.com/Bach-Stradivariu...:referralID=NA
This link seems to reinforce the "standard Strad with a gold brass bell" theory.
Bach 37S
Good luck!