This thing is very common in my experience. It is normal to receive a :
"XYZ radar, GABCD 10 north with zulu for landing"
"GABCD XYZ radar roger, QNH1013, Expect runway 26 report airfield in sight"
"GABCD wilco"
.....where no express class D entry clearance is given. In the past I have queried and asked "confirm GABCD is cleared into XYZ class delta", and have always received a "GABCD cleared into class delta, report airfield in sight".....but now don't bother. I would if there was any ambiguity.