Just looked at mine out of curiosity.
I guess this puts me in roughly Feb 1986 timeframe.
The 3 months Jan/Feb/Mar 96 not being assigned, but using the Apr start # 2291
and a total of 90 days (Jan-Mar) minus weekends (22 days) means they were producing on average 33 units per day. Does that seem reasonable?
That is probably as good of a guess as any. The Mark V 510 (and the now almost forgotten 505) were introduced in 1985 but I do not know in what month or the starting serial number.
Mark V 520 S/N 09-11-01 completely upgraded to Mark 7, with all SPT's & more.
Model 10ER S/N R64000 first one I restored on bench w/ Shopsmith metal ends & retractable casters. Has Speed Changer, Model 4E Jointer, Jig Saw with lamp, a complete set of original accessories & much more.
Model 10E S/N 1077 oldest one I have restored. On bench w/ Shopsmith metal ends & retractable casters.