Nothing to do with conversions i'm afraid.
the R1200gs Bikes from 12/02 - 10/07 (K25) with the type code 307 & 317 could be supplied either with float sensor or fuel strip
The trigger for which bikes got float( good) or strip (not good) was if the bike was specced with a trip / onboard computer option you got fuel strip
If the bike didn't have have the onboard computer specified , you got the pump / float unit
For the GSA (K25) 03/05 - 09/07 type code 0382 & 0397 the above also applies
For both varients GS & GSA from the model uplift in 2008 GS model codes 303 &313 GSA model codes 0380 & 0390 The only option was onboard computer so all fuel strips
From the model uplift in 2010 they went back to a float system
However there is overlap on the changes so bikes built / registered around model change dates may have one or the other system fitted
it is possible to change from strip to float, but it is also dependent if you have the right ZFE for the pin swap to be applied
The RT range does not have the right ZFE so can not be converted.