Currently, yes. MOSTLY because of the way the air frame underwent major redesign to accommodate the B variant. Before that happened, the C was just fine. At least on the drawing board. Just an A with bigger foldable wings and a tailhook. Once they started with an STOVL version, that all went to shit.

There was never a redesign for the B variant; or rather, none that had any real impact on the C variant.

Initially there were 2 programs:

The CALF Common Affordable Lightweight Fighter program, and the JAST Joint Advanced Strike Technology project.

CALF was basically meant to produce an F-35A / F-35B, although it wasn't called the Joint Strike Fighter and it looked like this. It was going to replace the Harrier and possibly replace some F-16s for the USAF.

The JAST was still undergoing conceptual design, but was intending to replace the F-16 and F/A-18 Hornet.

Both of these programs came about at the same time (around 1993) and Congress + the DoD decided that the JAST didn't need to be it's own program, or rather, that in the studies conducted for it, they determined that the JAST could be a CALF, with a carrier variant perhaps using larger wings or a modified wing.

They then joined the projects, set out new unified requirements and that became the Joint Strike Fighter program. There was a competition between Boeing and Lockheed (the X-32 vs the X-35) and the X-35 came out on top because it's vertical lift system was better, it had a better thrust-to-weight and it didn't require a wing redesign.

The only major redesigned that happened for the B variant was around 2008 or 2010 when it had gained too much weight. To fix that they redesigned parts, removed some, etc, but the only things that carried over to the A and C models were minor and had little or no impact on how they flew or how reliable they were.