Pretty much, the 1 GHz mod is a much more extensive upgrade - and it costs a lot more because of the Teledyne attenuator relays.
It's good to know the price difference between 500M and 1GHz versions is not just pure mark-up
Not pure ... let's just leave it at that. The R&D for a company the size of Keysight to develop a 1GHz scope is probably significant. It was done a long time ago though, just like the Megazoom IV.
I had all parts on hand for the 1GHz mod and decided to try the 500MHz first, which was simple. I've gotten used to 0402 and 0201 parts though so the component swaps were for BIG components. I thought I had marked photos of the 3000T to follow. Matter of fact, it was the 3000T because it was a 3014T but had footprints for the Teledyne relays. 3000A did not.
There are around 132 or so components for the 1GHz mod. I would have done it but finally, a pristine 3104T appeared and with option bundle to boot. Someone on here grabbed the parts just to get the 4 relays in the set.