Yes, it *could* just be a fused blob, but its also possible to blow the GP5 (pin 2) I/O driver upper MOSFET and end up with a dead short to Vdd (pin 1), without killing the core and the other pins, so it still 'works' as long as that pin's function is non-critical.
However, my and Rstofer's point is that even if it is working enough for ICSP (i.e. the programmer returns the device ID and the CONFIG word successfully), if it is protected, its a dead end as the code cant be recovered by ordinary mortals, and manufacturers that don't protect their closed source code are significantly rarer than hens teeth!