Trying to find info for Shotgun

[Barry E. Scheetz]

Greetings. I have been reading some of the posts and have been impressed with the depth of knowledge of the responses that I have seen. I have gotten into the Parker collecting through the back door. A few years ago, a former colleague of mine left an early production back lock hammer gun to me in his will when he passed. the serial number is O1677. Recently I was fortunate enough to find and purchase another early manufacture back lock hammer gun, serial O925. Both of these I understand were the lowest quality guns manufactured as designated by the "O" prefix on the serial number.

I am particularly interested in the latest purchase since it carries 20" barrels and is marked "Penn RR #29" and has the name "Fred Gren" inscribed on the trigger guard. I am assuming that the name is the PRR railroad policeman use used the shotgun.

How common on these coach gun? The gun has a "T" stamped above the serial number on the water table. Is there any significance to this marking?

Thanks in advance for any input that you all can provide.

Barry