24 inch 390 channel balance

Hey, Joe. Usually a stamp of 23 C corresponds to our 2330, yes. However, you should weigh your window sash and compare it to the weight rating chart under the S390-24 just to make sure it's correct, as there is no guarantee.

Yes, you would need to remove the sash and physically weigh it. You would not divide the weight by half, though. Not for this type of balance, at any rate. The option chart under the S390-24 is based around two balances per sash working together as one unit to carry each respective weight.

They look pretty close, yes, but I can't say for sure. It's hard to eyeball what the depth of the bottom shoe is, so without knowing its exact dimensions I can't say if its the 15-001 or 15-002.