Channel Balance Replacement

I pulled 6 channel balances out of 3 windows. Four of them are numbered 2240Z and two are numbered 2240. The 2240Z's appear to be newer. The 2240 and 2240Z were mixed together in 2 windows so my best guess is that the 2240's are old and that the 2240Z's were used as replacements sometime in the past (based on the age of the parts). They are in non-tilt windows. They are 23 inch.

The only difference that I can see between the 2240 and 2240Z is in the lower fitting (see photos). The 2240Z seems to come to more of a point. I looked at your guide and wasn't sure which channel balance to order series 351 or series 390) or if I needed a special order since neither of the bottom fittings seem to be exactly identical. Thanks for the help.

PS The 2240Z is in the foreground of the photos and the 2240 is in the background.

The shoes on the 2240Z are 1 1/8" like the 15-001. The shoes on the 2240 are 1 1/16" which may be due to wear since they appear to be older and worn.

Thanks for the help. None of these windows had take out clips installed. How can I tell which take out clips to order?