Based on my research for my 1991 EGR 240 I believe the only difference between EGR and NON-EGR head pipes is where the head pipe connects to the catalytic converter. My recent research indicates the fitting at the catalytic converter end is different for an EGR head pipe because it is designed to connect to an original EGR catalytic converter (which apparently were larger than non-EGR converters). If you have both an EGR head pipe and EGR converter to put in that are in good shape, and the catalytic converter has the oxygen sensor port at the front (I'd compare with your old one that you'll remove) I think you'll be okay. However, I've found that accurate EGR knowledge is hard to come by for 240s so possibly I am missing something.

I would suggest having many extra rubber exhaust connectors on hand 666407 since they can be easy to break when mounting the front muffler. Depending on the tools you have, and availability of a blowtorch like muffler shops use, you may need to pull out the whole exhaust from under the car after you disconnect the head pipe bolts and rubber mounts, in order to disconnect the old catalytic converter from the front muffler - that's how I did it a couple weeks ago anyways. (Volvo 666407, front muffler, & Volvo 1206468, rear muffler, and exhaust clamp 976587 - or one of similar size). Also, there's the head pipe gasket Volvo 3531326. (Part numbers are for my 91 but I think they're the same for 93.)