Anybody know if there exists a serial number chart for vintage Neumann mics ? Like the ones available for old grand pianos where you can look up the serial number and get to know the year it's manufactured in. Just out of curiosity (no big deal if I never know) I'd like to know what year my vintage Neumann is made. The serial number is there so it should not be impossible... Any tips ?

Hi does anyone know a good repair person who look over and rack 2xCalrec PQ1061s, a Neve 33314a and a Calrec C1204. I would really appreciate any information as I have some other gear such as a Cadac board and some Glensound pres that will also need work.
Many thanks,
Warren