As far as I can remember, Progress always marketed their database as that it does not need a dedicated DBA. IMHO, depending on the system, that is not really true. Nevertheless I agree with Cringer in that most companies wouldn't hire a dedicated Progress DBA just for his DBA skills. Plus, modern applications are maybe not build client/server anymore and may involve the AppServer or are even Web applications. Therefore you should make yourself familiar with the Progress AppServer and I can only second Cringer in that you should make yourself familiar with the ABL.
Progress installations and knowledge, both DBA and application development, is not spread widely therefore not many companies are looking for out. But the ones that do are having a hard time to find seasoned pros.
Heavy Regards, RealHeavyDude.