I had 4 and they gave me another one at HCM. They also require ALL the documents they mention. I'd advise anyone to make sure they take them all. They're very strict on that.
I got a bus from the border, Thai side. On the left as walking out. I remember the bus was either Nok Air branded or the seats were! Was about 6 months ago. Hope that helps.
They wanted all the details specified on the website when I went. Tickets, bank statement, the lot. I’d have it all, just in case. This was about 12 weeks ago.