An emissions/powertrain/chassis code that they can't read? That is odd. I would guess they can, I would just try again, and watch for the numerical display of the code and remember it. They told me somethign similar with my 2000 Grand Marquis before I got a way to read them myself, but I just snuck a peek (they tried to keep it hidden, super secret or something). Just because they can't make anything out of the number, doesn't mean it can't be done.
So they did atleast use an OBD-II reader, generally when you tell them you have a 94 or 95, they will say they can't read them (since other than exceptions to the rule, like our 4.6 powered cars) they are OBD-I.
97 Mark VIII LSC/Silver/Gray leather
97 Cougar 4.6 Sport/White Opalescent Tricoat Metallic /Gray leather down but not out?
89 Cougar LS 3.8/Oxford White/Gray velour/HG need replaced AGAIN
00 Grand Marquis LS/Vibrant White/Gray velour
63 Falcon 302/black and rust/shed isn't moving
82 F-150/Oxford White/dumb VV carb doesn't pass emissions