One sure way is to check the lettering of "Squier". On the Classic Vibe 50s and 60s (as well as the Matt Freeman sig), "Squier" is gold-colored logo. I could be mistaken, but a VM's brand logo appears to me as kind of bronze-ish. Worth noting is the font of "Precision Bass". On a CV, it is block letters and in a rather straight line. Affinity is black lettering on the logo, and is designated as "P-Bass".
What finishes are you seeing? The CV 50s come in lake placid blue or butterscotch blonde. The 60s have either sonic blue (OOP) and fiesta red.
Another tell-tale is the color and/or gloss of the neck and headstock: the 60s Precisions have a darker, almost
orangey tint. The 50s is untinted, but glossy. I'm sure I'm missing a detail or two, but this is a starting point to help you distinguish a CV from other products.
The photos are headstocks of a 50's P and 60s P, but the same principle applies: