NEVER TRUST SERVICE CENTER ADVICE.
(At least for anything remotely technical)
Tesla's reps are overly trained to "bullsh^t things they don't know, that sound plausible, to make people go away".
The digit extension at the end refers to the "variant" of the same basic ECU. -80- is the "stripped" ECU - it has no PLC modem, thus isn't CCS capable. This has been mentioned several times and indeed is even in the first post. Don't get the -80- version. Functionally, at the moment, they're correct... the -80-B version has no more or less features than the -00-B, as Tesla exists today -- without formally acknowledging (and in fact, formally denying in every way) the CCS functionality. Except, when you get the -80-B, you'll get "CCS adapter support: Not installed". Bit of a difference, yeah!
I have a saved search on eBay for the base part number ("tesla 1537264"), and I recently noticed one ECU go up. That's the -80- version. Whoever buys it will be disappointed. It was probably from someone that just upgraded their car with an -00- version to get CCS
Don't tell Tesla why you want it (see #1: never trust service center advice). Feel free to tell them what you did later, though - if you want to impress them. They love to make-sh^t-up, but they're even happier to learn from concrete evidence (a 2018 Model 3, saying CCS enabled, with a 1537264-00-B ECU, that charges perfectly normally in all modes). But it's "guilty until proven innocent" with them for good reason - people very frequently stumble into a service center having just completed a full frontal lobotomy, and they need to be held through every step of every menial task. Or they read and misinterpreted something somewhere on the internet (I wonder how prevalent that is for this thread...)
If in doubt, ask here.