Stock MAF do not have a "calibration". The 94/95 GT and Cobra use the EXACT same MAF even though the GT uses 19lbers and the Cobra 24lbers. The actual calibration is done in the ECU.
Good call, what did you use for a bracket to hold the filter and MAF up? Maybe just some flat stock bet from the bolt that holds the air box to the inner fender and then use one of the MAF nuts to hold it?