2 questions...

Were any of the later seasons done in color?

Was this show taped or filmed?

All 143 episodes were in Black & White.

I don't know, but I'd guess Film.

All 143 episodes were on B&W film. Mr. Ed was one of only four CBS sitcoms that were still in B&W during the 1965-66 tv seasons, and it was the only sitcom not aired in primetime, since it aired Sundays at 4PM ET. The other CBS sitcoms still in B&W that year (all ended at the end of that season) were The Dick Van Dyke Show, The Munsters, and The Smothers Brothers Show.

Until All In The Family in the early 70's ALL sitcoms were done on film, and most still were well after that, including some of the studio audience ones still too.

The show ended in 1966--which was the last TV season for black-and-white shows. Many fine shows of that era likewise ended, prior to the all-color switchover: Dick van Dyke; The Addams Family; The Munsters; Dobie Gillis; etc. Never having been seen on color TV, Mr. Ed was regarded, by many, to be a WHITE horse, instead of the rich golden hue of the palamino that he was ( I know that I was surprised, when I saw my autographed photo of him! Surprising, also, that it was hand-signed! ). On Saturday Night Live, they used a white horse.

NBC shows, were, yes, in color earlier, because of the RCA TV connection ( NBC and RCA were [ ARE STILL? ] in business together --so they'd promoted color, in the 1950s.
NBC/RCA had worked in creating TV together, too ( yeah, yeah, while Philo T Farnsworth was creating a TV in his San Francisco home--broadcasting a video horizontal line, David Sarnoff and Vladimir K. Zworykin made TV history, with a broadcast of a statue of --who?? Why my very own AVATAR, Felix the Cat!
in 1928 )
http://www.mztv.com/pioneers.html.

What really put the crimp in TV was WWII... the 39 NYC Worlds Fair and some sports were televised... but then all ended until after the war.
RCA did not invent TV... they did get the patent to the ultimately accepted color standard so yes they did more first, and the majority of the first color sets.

RCA has not been part of NBC since the late 70's or early 80's... it has since been owned by GE who were by the way the ORIGINAL owners... but saw little value in those turmultuos early days and sold it off.

Then again RCA doesn't really exist anymore either except as a holding company for off shore produced goods.... the last RCA American made TV was sold at about the same time the network was sold back to GE.

And yes Felix was one of the first TV icons... but not the electronic system we know today... that image was from actually one of the early mechanically scanned systems.... (that as I recalll CBS was helping work on)

As to Farnsworth that was much more FM radio he got screwwed out of... though he may have been involved experimentally as an employee in TV.

Which would almost make sense as TV audio is FM (The picture is AM.... and why you get a static filled picture before audio is a problem)