Quality Rubber Parts Source - Opinions please

[66 GMC 351E]

I'm looking for quality rubber parts for my '66 GMC LWB wideside truck. Trying to avoid imported junk and LMC because I've heard nothing but bad reviews on their rubber parts. Purchased a cab kit from Precision Restoration Parts and I've been looking at Steele, but I haven't been able to locate some of the grommets and seals. Looking specifically for inner fender seals, fender to cab seals and inner fender mounting grommets right now and will need other rubber parts as well. Classic Parts has them online, but I haven't pulled the trigger. Anyone have experience with these parts from Classic Parts or can someone recommend a better source? Brothers has some of them and they say, "made in USA" on some, others don't so I'm thinking they are imported. I'm in the desert where the sun and heat is murder on rubber parts. I don't want to be replacing these parts in a year because they've all cracked. Thanks in advance for your responses.