My first pocket watch and my first watch purchase from eBay

hi All
I just now bought this pocket watch and am very excited. I had always wanted a pocket watch ( even before I wanted a Swiss watch ) and so this purchase is special to me.
Its an llinois 12S Art Deco Pocket watch Sunburst dial and per seller in excellent running condition.

However, from the photos that seller provided I see two numbers - 275817 ( on the caseback ) and 4075260 ( on the movement ) and they both check out on pocketwatchdatabase.com.
First no dates it to 1887 whereas second no. dates it to 1922. Could it be that the caseback is a replacement ? In any case, I am fine as this looks to be a legit watch 😀

Can you guys please tell me how did I do here ? And any tips to take care of it, need ( and place ) of servicing etc ?

It looks good to me.

early American pocketwatches.

quite often the sales outlet would purchase "bulk" movements from a company like Illinois or Waltham or whoever and then offer to case the movement in a case that the consumer could afford. Hence the profusion of 9/10/14k rolled gold/gold filled PW cases you see on the market at this price point. The 25 year guarantee is the classic marker for this. this is very common in period.

Yes, all of these companies also sold pocketwatches already cased. Whether these factory cased PW's are intrinsically more valuable than a dealer cased watch is debatable. as per any watch (unless it is significantly rare or desirable) condition is the pre-eminent aspect of any purchase.

the issue of serviceability of the movement. 17 jewel movements by any of the US manufacturers are predominantly middle market models. Many service parts (staffs/stems/mainsprings) are available for these models inside the American system. If they aren't a competent watchmaker can fashion such parts (maybe not the mainspring) for a price.

size 12 was customarily worn as a dress watch so it is also a little small for a daily wearer. Most common are size 16 or 18.

Illinois are a good brand. Their RR models are very good (as are any of the american RR models).

nice watch.

Congrats. I really like big manual wind movements.

Mine arrived 45 min ago amd after i gave it a wind, it has been running strong since then.
It looks as beuatiful as in the pictures that selller posted on ebay( I initially had thought he might have edited them).
Here are the pictures in my hand -