This is correct, i have recently done it at Rayong. Your employer needs to provide you with a form when you leave, a Kor Tor 10 (spelling??) if your employer did not give you, you can go upstairs to second floor in the One Stop Centre at Mapthaput and get it from there, take that with you to SSO in Rayong along with Passport, Thai bank book, Pink ID card and Yellow book, they will complete the forms for you, you just have to sign. But this must be done within 6 months of leaving your employment. If you have been paying in for less than 15 years they give you a "lump sum pension" paid into your bank in about 1 month. At the same visit i registered to continue payments by myself, received the papers with my new number, then through the back to the finance department and did my first contribution, i now pay at 7/11 every month. For SCB, my bank(i also have UOB but they would not pay it into there), they gave me a form for the branch manager to sign so they could automatically take monthly payments, but they said not all branch managers will sign it!
Rayong SSO is great, really helpful, i was in and out in less than half an hour!