Essentially yes, second hand or DIY.
It does depend what part of the Buchla sound you are attracted to as to which of those two options might be the right one for you. I was really into the digital screwed up-ness of the 259e and not so much the "vintage" analogue stuff.
But can do a lot in Euro these days that would get you pretty close to either.
Of course you then have to take into consideration the interface itself which is one of the things that really sets Buchla apart from other formats.