Do you mean ABA players who entered the NBA before the merger (Charlie Scott, Jim Ard), in the merger to another NBA team before the Celtics (M L Carr), or in the merger directly to the Celtics? There are other names, but I checked only up to 1980. The league is now diluted because players used to stay in college for 4 years.
If you say nobody, I believe you. I'm just saying that former ABA players were Celtics in the years both before and after the merger.