I have one of these low number 1888 trapdoors myself which is right in the middle of the range of low numbers and here's what I found about them. Yours seems to be in the right s/n block for this being just north of 145K...
HOW FAR APART MAY SERIAL NUMBER & CARTOUCHE DATE SAFELY BE?
So far as general circumstances are concerned, the serial number SHOULD agree with the date (1877 and later, only) on the Master Armorer¹s cartouche. The PRODUCTION DATA given on the home page of this web site gives the best correlation thus far presented. If your serial number is +/- 1500 digits from a designated final production number for a given year, that is considered acceptable because the serial numbering of receivers was to be about a month ahead of production. Thus, depending on which box of receivers was grabbed first, you can have variations of this order of magnitude.
There are two notable exceptions to this rule, and both involve the final model of the trapdoor, the MODEL 1888 Rod-bayonet Rifle. A number (too many to be chance) of arms in the 97,000 - 145,000 range have been found, frequently in fine condition, in this configuration. Clearly, these represent "sweeping out the shop, or since there are so many, possibly disassembling the older model arms". Another group of "out-of-step" M1888 numbers (in the low 300,000 range) also occurs - these are the remains of the 1,000 Model 1884 Experimental Rod-bayonet Rifles, which were scrapped and rebuilt. This is further confirmed by the fact that original unaltered M1884RRB specimens are nearly nonexistent (far and away the rarest SA experimental arm, among those made in similar quantities).
