Well I hate to disagree with Christian, but in my experience the issue with keels needing to be dropped is a common one. And also there IS a design flaw that allows the interior pan and cabin sole to sag and throw off the cabinetry and door jams. Our 1989 model 38-200 had all these issues.
Right after we bought the boat we had water running down the from the keel joint with the boat on the hard, and when you lifted the boat in the slings the back foot or so of the keel separated from the joint and was unsupported. Based on this we had the keel dropped, and rebedded with epoxy. Which worked perfectly, as after that the bilge was dusty dry (except when it rained) and the keel no longer separated at the rear. The apparent need to add additional support to the rear of the keel is why our yard suggested using epoxy, not just caulk, to do the bedding. In our case there was clear evidence that the original mold release had not be removed from the bottom of the hull prior to mounting the keel, and there was even a paper label on the surface under the failed caulk. This might be unique to our hull, but I doubt it.
As for the design defect on the hull. After the boat was in the water awhile the cabin sole would sag, about 2 cm or so. You could see this on the side of the galley cabinetry, as the floor would drop, but the cabinet side would not move, exposing fresh cabinet side. And after this the door to the V-berth would no longer close. All of this went away every fall when the boat was hauled for the winter and placed on the hard on the keel. I contacted the factory and asked about it and they said they had seen this on other 38s, and called it "subsidence". They said that one owner had gone so far as to have a pipe engineered that tied the floor pan to the overhead to add additional support. But their attitude towards the issue was that while there was subsidence, it wasn't progressive. That is, once the hull shape had deformed a bit, it stabilized, and didn't get any worse. And as disconcerting as it was, the only real manifestation was that the V-berth door would not close.
I wouldn't let these issues deter someone from purchasing a 38, but I would sure look for them.