"He didn't have time to look in the box?". Statements like that from sellers put me in buyer-beware mode.

Price guide here:

http://www.antiquecameras.net/rolleiflex.html

Unless he can tell you the serial number and answer questions as to when last servicing was this is not a screaming deal and actually could be a little pricey. But I'm one who has patiently bought Rolleiflexes for over 15 years and have found them as cheap as $150 for 2.8 Planar versions, and I've heard and seen it all (I have at least 8 Rolleiflex TLRs). Unless you can examine it closely or be certain of last service from a reputable seller, be patient.