Well, it depends on, which 88 are you talking about. The 'classic' 88 was indeed developed as an AA gun, and then it was made capable to engage ground targets after the lessons learned in Spain. Ie, this is the FlaK 18, 36, and 37 designs I am speaking of, which found their way into the Tiger I as well in a modified form of KwK 36. It was manufactured in vast quantities.
However, there was also another 88 gun, developed from start as an AT gun : the PaK 43. It had a LOT longer barrel than the formet AA gun (L/71 vs. L/56, i.e 6m+ barrel!) and was mounted in the Ferdinand and Nashorn tank destroyers, and also as a oridnary AT gun on carriage. This was never used as an AA gun, altough again there was similiar, but different design, the FlaK 41, which had slightly longer barrel (L/74 IIRC) and perfromance, employed as AA gun, but could be also used as a AT gun like the FlaK 18/36/37. AND there was a 3rd different long 88 gun, the KwK 43 for tanks, being different from the PaK 43, altough it used the same ammunititon, barrel lenght and performance was identical; this is what the JagdPanther and Konigstiger mounted.