Thanks for your insight.
I thought as much. Although, Vigor (an aftermarket brand I found online with claims if 20 years experience) lists one item for both part numbers: https://www.amazon.com/dp/B08QRMQ83Y/ref=cm_sw_r_apan_glt_fabc_D54STH8VYDDDVN5CQZ6Y
However, Arnott (top rated aftermarket brand) does not have any listing for the Security Plus part number and does not list it as interchangeable for the regular part number.
Looking like car owner will have to cough up about $400 a piece for genuine BMW 37126795014.
Yeah, I see what you're saying. I found the Vigor part on Amazon (US link).
https://www.amazon.com/37126795013-Right-Spring-Compatible-37126795014/dp/B08QRMQ83Y
Now that I'm actually looking at it, it doesn't seem to have much going on with it, in that it looks like it's just an airbag and made almost entirely of rubber.
FWIW, the Vigor part is listed as "compatible with 37126795014" so perhaps it would work.
They also say "contact us directly" so perhaps, if you can find a phone number, give them a call and ask about your specific case.