Appears it worked emailing him.
Here is his added response on his ebay posting.
"On Dec-17-06 at 18:30:03 PST, seller added the following information:
I have received several email regarding this plate. It is not an original steam locomotive number plate but was made as a copy of the original and sold by the Colorado Railroad Museum. I have no intention of trying to decieve anyone as to its originality as evidenced by the comment in my description asking for clarification, and now I have it so bid accordingly. Thanks. This is a copy from an original pattern as a miniature version of the
original full size D&RGW 346 from the Colorado RR
Museum in Golden, CO. There were several solid cast bronze plates plates produced for them in the 1960's."