Yes, the camera has a internal IR blocking filter called a "Hot Mirror". Yes, this has been physically removed and replaced by a clear piece of glass which is known as the Full Spectrum Conversion. You then use an external IR filter on the lens to put the camera into the various IR spectrums. You can also replace the internal hot mirror with a dedicated internal IR filter, say a 590nm. The Full spectrum conversion you can also put an external hot mirror (B+W 486 or the Max Max CC1) to make the camera color again! With a converted camera like the 2 described here the camera takes normal exposures and can be hand held. If you leave the internal hot mirror in place and put a external IR filter on the lens then you have to overcome the effects of the hot mirror and are looking at VERY LONG exposures .
My blog has a discount code for Spencers Camera to do these conversions but others will do them as well. Good luck.