The LE14A cones should be white, so unless they were painted they were reconed when refoamed. If reconed with LE14H cones (which are black with the foams on the back of the cones) then great! This is possible as JBL actually would repair all the bad surrounds (with a recone!) on LE14As for FREE if you were the original owner (this practice stopped in the early 80s). As well, LE14H recone kits were in stock all through the 1990s, so if they were repaired by a good JBL dealer back then, then proper cones would go in (JBL offically never refoams, only recones are accepted). If some sort of generic cone was used, well, it's not so good, and perhaps bad. The cone should have the 'Aquaplas' coating on the front (and back?) whether black or white in color. I'd ask the seller to remove the woofers so you can inspect the back of the cone. From the location of the ribs on the cones, they do look right, a part number from the back would say so for sure. Maybe they have a receipt for repairs that explains what happened? If the foams are on the front of the cones and the cones look painted, then they are then most likely the original cones but perhaps repaired in some way (as a guess).
However, even if the cones are not 'right' at $150 I'd still buy them if the cabinets were excellent mostly because the cabinets are really well made, the tweeters are worth decent $$, and if needed proper LE14As can be had for under $200 and refoamed for $30. Decent pairs of Lancer 99s have sold for over $400, but typically $200 to $300. Of course for $300 you can buy better speakers, but if they fit into the vintage system you've got so what! The also make excellent 'ewave' projects.