series 145 balance spring; unsure of lbs

A quick learner from California says:
Thank you in advance for your help!

I want to replace the coil balances here for what I believe is a "sideload" system, but I'm unsure of what lb springs I need. In the picture, I think there is a six stamped faintly into the end of the spring, but I'm not sure if it might be a 9 (and I'm just holding it upside down). Is there a way to tell?

And just to double-check: the plastic piece is the Double Side Load Carrier (product code 15-102 ), right?

Thank you!
User submitted a photo of window hardware.
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Paul from SWISCO responded:
Hey, Arnie. I would wager that's a "6" on your spring. It looks like you have our Series 145 spring, and the heaviest they make for these is "7."
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