Thanks for the input, folks. Mehul must be either very sharp-eyed or else clairvoyant to know that I just signed up for the forum - probably some of both, knowing him. Mehul is my unofficial PR agent since his flattering commentaries always makes me feel like a Prince.
The old 6-bore, now 5 bore due to who-knows-what, is almost completely disassembled now, except for removing the nipples -still stubbornly in place - and the tin? and copper wrap on the forend which seems glued on. Excess solder between muzzles now off and the amount of wear and pitting all around both openings indicates very strongly that the barrels have never been cut down and are original length (24"). Careful, tedious rust removal by a technique I developed for myself has left a great deal of the original browning intact. Barrels and locks look pretty good, whereas buttplate is significantly pitted. This is not uncommon.
The well reinforced ramrod (both ends) is also the proper length for the barrels, and has a ball-pulling screw on the end rather than the worm that might be found on a shotgun. Overall weight of gun, truely massive short barrels, and ramrod all point to initial life as a dangerous game gun, yet I suspect it did see use as a fowler in California once its former life was done. A learned colleague in England says the most likely scenario is that it first went to India for dangerous game, then went with someone from there to America. Many is the gun which has seen more usages than that for which it was originally built.
Any and all input, references or pics relating to these old ML big-bores will be greatly appreciated.
Aloha, Ka'imiloa