39-099 vs 39-343

A home owner from Atlanta, GA, USA says:
Hello. I need to order the correct part. I've read the other threads and I understand the difference is based upon when the window was mfgr. However this house was built in 98 and 99 so I'm not sure which windows we have. From looking at the two pictures, both parts seem identical. The screw holes are the same, and the shaft length and other dimensions are the same. Am I missing something. Are they different? Thank you so much.
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Dave Sr. from SWISCO responded:
The two operators are very similar, but do have subtle differences. One easy way to confirm is to look at the corner of the glass in the sash see if the date is etched there. There may also be a tag somewhere on the window that tells you its age.
A quick learner from Atlanta says:
Thank you!

This is all I see on the window....

architemp tempured ansi 297.1-1984 16 cfr 12-1-ch, cig 1-2-97.6 Anderson high performance 1GCC CBA IGMAC

Does that mean 1997?

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Dave Sr. from SWISCO responded:
Thanks! Yes, I believe it could be January 1st, 1997. If so, we recommend the 39-343 .
Anatomy of a casement window
Anatomy of a casement window
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