Has anyone seen a week 53 production Rhodes?

[wolverine2013]

Rhodes experts - I need your best intel! I've come across a Mark II stage 88-key with a date stamp of 5383.  Not a typo, not a smudge - a crystal clear 5383.  Can anyone tell me how this would even be possible?

Pic is below.

[The Real MC]

Not impossible.

Mark V pianos were only in production from 1984 to 1985.  Mark II pianos were still made in 1983.  Someone on the production line probably didn't bother to look twice at the stamp.  "5383" could be the 1st week of 1984.

[wolverine2013]

Indeed TRM - I had to pull out the calendar and look at this closely. It turns out for every 365 day year, if they started week 1 on Jan 1, then dec 31st is the only day that falls on week 53.  I assume this must mean any Rhodes with a week 53 stamp, must have been completed on Dec 31st.

Interestingly, unless it is a leap year, no other days can fall in week 53 regardless of what day Jan 1-7 they would have started the week count.