Definitely have it repaired if you can find a watchmaker with the parts. No sense in having a nice watch like this that is not serviceable. The staff is not a problem as they made a great deal of these and the staffs broke a lot. These watches are not shock proof so if it is dropped there is about an 88% chance that the staff will break (my personal experience, ha ha). The escape wheel may be more difficult but it can be had as well. It will not affect its "originality" to have the escape wheel and balance staff replaced, just as putting a new crankshaft and replacing the clutch in a vintage car, would not alter the originality of that. These are just maintenance and necessary for proper working of the watch. It make cost you a couple of hundred but I would get it fixed. Try and get us a photo so that we can be of more assistance.

The engravings if they are "scratched in" are repair marks if they are Roman and Arabic block engravings that look like a stamp they are factory and designate the date. The problem is that the numbers back then were restarted at 0 when they reached one million. So it may look like a 20's 30's number and actually be in the 50's. We would add a 1 and enough zeros to take up the space to make a 7 digit number and then go to the list of dates. Just looking at your note I realize that your number is lower than 28,000 so, if my knowledge is correct, it could not be an Oyster case unless it is from the 50's as Rolex started oyster case numbering in 1926 with 28,000, so add the one and zeros to adjust.

Hope this helps.