There isn't a chart for the FWB Sport unfortunately, unlike the FWB match rifles. But quite a few people have contacted FWB direct for dates of manufacture so your best bet is to get as many as possible to post them up.
Even extrapolating dates between known serial numbers is inexact because, it seems, rates of production weren't consistent during the rifle's <15-year(?) run. The first production models seem to have been issued in about 1973 and the last ones some time in the second half of the 1980s.
But it's quite possible there was a slow start and a long tailing off of demand, with a bulge in production between, let's say, 1977 and 1982. Others will have a better idea than me on these dates.
From what I can work out, about five out of six of all FWB Sports were made before the end of 1982, although they were still on sale new in the UK for quite a few years after that.
There's also the complication that the UK distributor and then dealers may have had stock on the shelves for quite some time before the rifles were bought by the end user. So when a rifle was bought new doesn't necessarily say much about when it was made.
Serial numbers checked with FWB and mentioned on forums include:
51631 - 1983
49992 - Oct 1982
44001 - Sept 1981