I haven't used LMC vent Windows, but I have used plenty of their other products with mixed results.
I will tell you that I have talked to multiple people that have had their vent window assemblies restored by Precision Rubber. It's roughly the same price as the LMC units. They disassemble, powder coat the frames or polish the chrome, new glass and rubber. The guys I've talked to at shows say they are perfect with no wind noise.
Sorry, I know it doesn't really answer your original question, I just wanted to let you know there are other options that you may not know about.