Does anyon have access to the Marlin records as far as model 1881 lever actions were configured? I have one that too me looks original and untouched but with a 21 1/2 " barrel and a short mag. I know most were made with a 28 inch barrel
Any help appreciated
Mike

Records for Marlin model 1881 rifles are incomplete. If your 1881 has a serial number below 4096 it will not be recorded in Marlin records. The link to Marlinowners is a great site, but they can't give you the factory data, as nobody there has any better access than you have.
Marlin firearms Collector's Assn. has the factory records, as does the Cody Museum. If your 1881 is serial numbered above 4096 then either place can confirm it's original configuration. That said, I can tell you it will most likely show the barrel has been bobbed, as early Marlins were not offered in odd number barrel lengths, and a 21.5" barrel would not be factory. 
Generally the old Marlins will measure 1/4-5/16" over an even number length, so it would be either 20" or 22", not 21.5" length. There is one exception 21.5" barreled 1881 in the records, 2-22", and 4-20". I assume you're measuring the barrel length by putting a cleaning rod down the bore to touch the breechblock face, and then measuring the rod. That is the method Marlin used.
PS-There were also only 194 half mags listed in the records. 
PSS-If you send me the mag tube length from the end of the forearm cap to the tube end, I can measure one of my short mag 1881's and tell you if your's is correct length.

The "fire in the plant" story seems to be a myth Dick. Marlin just didn't keep records until they incorporated in 1881, so the first 4096 guns were built prior to that time.
For some reason after John died and the two sons took over in 1906 they stopped keeping records again. So records are only available from 4096 to 355,600 serial number ranges.
To further confuse things; Marlin mixed all the models together amongst the serial number ranges, so no serial number ranges within a certain model. And only a handful of Ballards were ever listed in the records out of tens of  thousands built. There are also huge blocks of serial numbers entered into the records with no info added also. These blocks of numbers are often 20 guns, and unfortunate for the collector who has one in that range.
Special order guns occasionally didn't get listed in the records also. I assume this was because they were ordered specially by a customer, so they went right out the door, and not to the warehuse, so no reason to record the info for future reference. I've got an engraved deluxe 1893, and unfortunately it doesn't have any info entered by the serial number. Got a few other deluxe special orders that are also blank in the records.