IGBT Identifying

Here's an esoteric question...is there a way to visually identify IGBT transistors when they're installed in an amp? I have one of the last of the Forte' amps (Model 55) and was told it has MOSFETs instead of the IGBTs that Forte' used in a lot of amps. The manual says IGBTs...is there a way to tell from the markings on the transistors themselves? Thanks in advance.