If it's A3/B4, it won't be an issue with a 7.3 of your vintage. After all, that's the base spec for a whack of European diesel engines on North American roads, at least before the C sequences became more relevant and DPF and the like took over.
It would be fine, but in the grand scheme of things, there are much more cost effective options over the long term. Now, this is a clearance special, so if you got some, use it up. I wouldn't seek it on a regular basis, though. There are more suitable options.
If you're looking for something you can see in a VOA to determine an oil specification, you're not going to find it. And, as Overkill points out, SN tells you absolutely nothing about suitability for a diesel engine. The only thing of any use here, not just for this lube, but in a more general sense, would be the B4 part of A3/B4. If it said CF on the back, it might be something, too, but CF wasn't fantastic, and probably was the spec before or two before what your 7.3 calls for. The B4 is the only thing you have going for you.