I have one marked the same as jtrent's, but the markings may not be stamped in the same receiver locations. Serial no is 36616. The firing pin doesn't retract on its own but I have never fired or disassembled it.
On the left upper front of the receiver is stamped PAT FEB 20 & 27, 1900. Immediately beneth that it says PAT MAY 14, 1901. Then above the trigger guard is stamped HARRINGTON & RICHARDSON ARMS CO. Below this it reads "WORCESTER MASS USA PAT FEB 20 & 27, 1900."
Barrel measures 32".
Here is a link to a post on the characteristics of the model 1900 aand 1908. http://www.thefirearmsforum.com/showthread.php?t=55936