Yes it is. An easy way to remember it is that it starts with a 76 and has 15 Or 16 digits (can't remember). There is multiple ways to find your player ID. You can do it like wilco did it or if you have logged on to the server once, you can go to the stats page, Search up your name, click on it and copy paste the player ID. I hope this helps. Good luck with your medic interview!!
This is the stats page of rpuk:
https://altis.roleplay.co.uk/index.php
Your stat page:
https://altis.roleplay.co.uk/getplayer.php?playerid=76561198061699593
Your player ID (the one you will use for every whitelisted faction on the server): 76561198061699593