Depends on what you mean by beat up and what you want to do for replacement other than cosmetic.
The bezel / duck bill that sticks out on your machine can be replaced.
The whole bill head that includes the above can be replaced
The S+ came out of factory with the DBV145 (early) and later the DBV200.
The main difference was that the 200 could accept bills 6 ways while the 145 could accept 2 ways.
The heads are interchangeable but the 200 needs a slightly bigger power supply (more amps).
There has been many currency revisions and the DBV200 is upgradable to all the new bills except the latest $100 with the magnetic security.
The S+ however is no longer a supported platform by IGT so they have stopped paying JCM (Japanese Cash Machine, the maker of the DBV/WBA) for updates to the firmware so the set of currency available is all your ever going to get. The same DBV used in the S2000 platform can run newer bills.
When I say the "same" The S+ uses protocol 21, the newer S2000 uses protocol 24 which are different firmware's on the same DBV200 hardware.
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One other comment that is probably not relevant to your home environment is that the security of the DBV doesn't have magnetic sensors so it is not as secure as newer platforms against counterfeiting.
The WBA (World Bill Acceptor) series of validators (versions 11, 12 or 13) will work with the S+ platform and do support magnetic sensing but just like earlier platforms - no new firmware has been made for the latest bills for the S+ platform so if new bills come out your not going to be able to move forward. Newer WBAs models no longer have protocol 21 (S+ support) available.
If you want to move to a WBA you will need to replace both the bill head and transport. I also believe the cash can is different (I stand to be corrected) as the potential bill width is different.
WBA is world bill acceptor so it can be used for Euro's and other non US currency that may be of a different size (with the right firmware).
Finally we have seen on youtube a protocol convertor (no idea of price, haven't seen one for sale) that converts protocol 24 to 21 so newer validators supporting newer money could be used with the older platforms.