SeaSaltIceCream Your SIM doesn't have an IMEI. That's your device's identifier. SIMs have IMSIs, and no, regular sandboxed apps (which Play Services is on GrapheneOS) do not have access to identifiers like that as far as I'm aware.
Both your IMEI and IMSI are broadcasted to cell towers unless you use airplane mode, though, of course.
https://grapheneos.org/faq#cellular-tracking