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BTW just get the "regular" valve, unless you are crazy you are never going to go fording anyway and the extra cost is just not worth it.
EDIT here are pictures of the CDR valve, the first the valve is upside down that is the connection you are concerned with.
Before you EVER run it again replace the missing CDR valve, it sits on the pass side valve cover, go ahead and plug the hole going into the intake while you wait for it to arrive, one little nut, screw, washer etc. gets in there and the engine is DONE!
The filter housing may or may not have a drain depending if it had a fording kit, if it did you want to look and see if the CDR valve is gone, DIRECT entry into the intake, that should be your VERY first concern.
Most likely someone just needed a new filter and grabbed one out of the "bone yard"...
To actually answer your question, nobody can tell you if there has been any damage or not, engines can normally consume allot of particulate matter without issues, the biggest risk from sand would be cylinder wall damage, as long as it does not start to consume oil you are probably good.
Now...