I sold a horse that colicked 6 months prior. No surgery but 1 night in ICU and a 2nd night in the medical ward. No known reason but it was the only colic she ever had. Buyer never even asked questions about it.
Full disclosure to interested parties and you're fine. Horses colic all the time, outta the proverbial blue. The only time my OLD gelding coliced, he needed surgery. It was an intussusception. No history there, and no way to prevent. That's horses, right?
No surgery colic is ok as long as you have some honest idea of why. Moving is a decent reasonable reason
Could it have been sand colic? Sometimes the stress of moving or something like a 4th of July fireworks excitement day can bring on colic that actually is a sand colic. So maybe try using sand clear or something like that to prevent future possible recurrence.
I was standing with a sales horse in the arena, showing him to a prospective buyer. As soon as the buyer said, "I am really interested," Tex dropped to his knees and began to colic.
HAHA! What a jerk! I swear some horses are too smart. My mare pulls crap like this. We haul to a show or clinic, getting on the trailer she's sounder than sound. We get to our destination, she's LAME. I mean three legged lame. So we scratch, get back on the trailer and go home. Get home - sound - like magic!
She also did this recently when I had a friend come out to ride. I think she thought she was on the sale rack and proceeded to act like a total lunatic while we were free lunging her (keep in mind this is my 20 year old baby beginner lesson horse). Poor lady thought I was trying to kill her by suggesting she ride this horse.
OP - to answer your question - no. It wouldn't bother me too much. If you were willing to provide vet records with him, I'd feel all the better about it.