No there isn't. It's very easy to qualify for membership in SAG as virtually every feature-length movie is SAG compliant. The only filter they use is checking there's a legit paystub so you didn't just shoot a short in your bedroom and try to pass it off as a screen credit.

https://www.sagaftra.org/membership-benefits/steps-join

Worked over a decade in indie films, never heard of any producer having a problem getting SAG to recognize paperwork.

The barrier to entry is a $3k initiation fee. That seems steep, but lots of people could probably put together that much money if they needed it.

https://www.entertainmentcareers.net/acting/how-to-join-sag/