5513 What does the caseback tell me?

[jlovda]

For the first time since I purchased my 5513 in 1970 I got to see the inside of the case back. The outside of the back has my initials which were put there within a year after I got it so the case back was never changed without my knowledge. The SN is 204xxxx. It was serviced in 1972 RSC, NYC), 1980 (Sutters, Chgo) and 8/19 (Baschs, Clev). What does IV68 mean and who would have engraved 241 next to the 5513?

This watch seems to hold many mysteries since the SN indicates an mfg year much earlier than when I bought it.