There were several refits - even variations on the original FJ design as it initially appeared in the Technical Manual. Here's the chronology:
Federation Class Dreadnaught "Proposed"
- Initial FJ Design (for comparison)
Federation Class Dreadnaught "Production"
- Modified FJ Design (with rotated tertiary nacelle 90 degrees for warp field symmetry and continuity)
Federation Class Dreadnaught Upgrade "Proposed"
Federation Class Dreadnaught Upgrade "Production"
(someone thought the engine pylons were too low on the first version, so they raised them and made them horizontally linked across the top of the secondary hull - a sensible mod, IMHO)
Star League Class Dreadnaught
(Jackill's version - more true to the FJ original with the forward-facing shuttlebay)
And the short answer - aside from the fact that (IIRC) one FJ-named dreadnaught was mentioned in comm traffic out of Epsilon 9 in ST:TMP, all these designs are largely considered non-canon.