Also with this, realize that that ATc may also indicate the type of craft it is. While they could call it a jet, if the airline in particular operates more than 1 type of aircraft, they may have to indicate that in their call. Assuming UAL427 is a B737:
APP: UAL427, traffic 11 o'clock, 4 miles, 5000ft and descending, company Airbus.
Pilot: company in sight, UAL427.
APP: UAL427, follow company, cleared visual approach runway 25L.
Pilot: cleared visual behind the company, UAL427.
If the airline only uses 1 type of aircraft, you could hear them eliminate the aircraft type altogether. Southwest Airlines and Virgin Blue are good examples of this.
BL.