If you're talking about the HL2RP server, yes. You get PET flags (with the T being tooltrust) when donating. Don't remember if it's automatic, but it might be. Along with that, though, you get benefits on the other servers as well. A full list of benefits for GOLD or VIP can be found here. And yes, donations are permanent unless you abuse the privilages that are given to you. Then they'd probably get removed (IE: propspam, you'd get you PET flags removed).
Might go and donate then, could do with some PET flags.Would they be on outlands?