Tilt latch for replacement double hung

Hi, great idea. I wish I found this site years ago. Always afraid of ordering the wrong set and deal with the hassle of it or eat the cost. At this point I need about 10 sets so I'd like to get it rite. I believe I have the rite 1 what do you think? I'm looking at the 26-243 and 26-244.

The part I need is the tilt latch. Housing is "about"... 2 5/8" long X 3/4" wide X 1/2" deep. The identifying marks are a capital R or L. Identifying numbers under them vary, the 4 I took off had a 17, 20, 25 and a 27. There is a 00 on a tab near the end of the R ones. Nothing on the L's I looked at.

Thank you for the help, PS... I didn't order that part in the pic yet, just put it in the cart.