69 Powerglide painted number markings - what does it mean?

[digi-69]

I finally peeled back the grease from my original trans and saw big numbers painted on the bell housing.  The were painted black and were the following:  

9'17
33

The partial VIN matches my car (which I finally found - thanks to CRG), but those paint "marks" took me for a surprise.  

Your input is much appreciated.


Thanks,

Nick

[JohnZ]

Probably inspection marks and the test stand number.