I have an H grade 12ga with mis-matched #'s @ 73,342 & 73,338. For some time these have been the "Two" highest SN's recorded in the LACA SN list. With your other four numbers all being the same I suspect it was supposed to be matching, but somehow, somewhere got mis-stamped. The 35687 # should date it to around 1900. On the list of patent dates on the trigger guard is there a 1907 date?

Miller/TN
I Didn't Say Everything I Said, Yogi Berra