Sign Up vs. Add to Cart CTA for different product types’ product detail pages

So we have a webinar business that offers users the option to sign up for an upcoming webinar as well as a purchase a recording of a past webinar. Every webinar (upcoming and recorded) has it's own product detail page.

I am curious if it would be considered a best practice or intuitive to change the "sign up" CTA on the product detail page for upcoming webinars to "add to cart" for past webinar recording detail pages. My thought is that customers aren't actually "signing up" for a recorded webinar... they're just purchasing access to the recording.

Does this make sense to implement or am I only adding potential for confusion by having 2 different CTAs on these detail pages? I haven't seen any examples of this in the wild, so I was hoping for some thoughts/examples/direction from the group here.

Thanks!