During this period both geschwader had a mix of G-4s and G-6s (and some G-2s) and I recall seeing several images of G-4s belonging to JG52 (Hartmann) captioned as G-4/R6s (w/ gondolas) but I am unsure of the date[s]...
EDIT:
Over at
Falcon's 109 site there are several images of G-4/R-6s. This may not help you with an actual percentage or total number of gondola equipped 109s for 5 July '43 but it shows some JG 52 G-4s were such equipped leading up to that date.
Most Orbats I have seen for the LW at Kursk don't specify sub-type (just G-4, G-6 etc...)
I am sure you have seen Pavel's
Air Battle over Kursk 1943 site. In the lost list for JG 3 and JG 52 there are werk-numbers listed so you may be able to track down how many of those lost were equipped with gondolas.