80's Era 5513

[forgedblades]

Hello all. Need some input on an 80's era 5513 that belongs to my Father-in-Law. This Sub has been his since the early 80's when he purchased it new from a local AD. It has seen it's fair share of wear and has never been serviced etc. He actually promised me this watch upon his passing so it means a lot to me. Well after years of wear the watch stopped the other day(broken main spring I suspect) and since I will inherit the watch one day I felt obliged to service the watch as he was just going to put it in a drawer and let it set until the day I got it.
The bracelet is in need of work as well and I am going to send that to Michael Young for a refurb but question...Instead of separating the bracelet and watch would it just be easier for Mr. Young to do the service as well? I have read rave reviews as to his work on bracelets but really nothing I can recall as to service of the movement. Guidance and input would be appreciated.
Also I opened the watch and while the model number on the case is 5513 the back case has 5512 stamped in it. Is this common or has it been replaced at some point do you think. He said he could not remember ever taking it in for anything.
One more thing I noticed was the dial. In the right light it appears that the paint is crazing. See picture below. Is this a concern for the long term "health" of the dial?
Again thanks in advance for all your input and advice.
Dave