If I understand your question correctly, you’re asking if a dvd -R recorder can be made into a drive that can write to both -R and +R disks. Is this the correct interpretation? If that is your question, then the answer is no.
I have seen some discussions regarding the NEC 1100 using the 1300a firmware in hopes of adding -R capability to a +R recorder, but don’t remember any success stories with that strategy.
By the way, a dvd rom drive only reads dvd’s, it can’t write to them.
If you want to be able to write to both types of disks, the dual format drives are getting very inexpensive these days. The NEC 1300a is under $100.