I've changed the clocks on my Td5 from pre-facelift to facelift and they were quite different in some ways - for example the fuel & temp gauges read back to front ???! So I wouldn't be surprised if they didn't work - BUT its only a 10 min job to swap them so try it and see
I should clarify here that I'd tried using the fuel/temp gauges in the 'wrong' instrument cluster - my fuel temp needle on my pre facelift dash was bent when I changed the clear plastic front cover so I wanted to fit a replacement fuel guage which happened to come from a post facelift cluster. If you swap over the whole post facelift cluster then it works ok (I have post facelift instruments in my '99 now).
Its only if you mix the instruments within the cluster that you come a cropper. I mentioned it as its possible that using Td5 gauges in a 300Tdi might have similar issues.