PackRat-
I know I'm new here (less than 24 hours, to be exact), but being a media-type on sabbatical, I'll hazard a guess:
Jamie Lee Curtis is married to one Christopher Guest, a/k/a Nigel Tufnel in the Spinal Tap movie/albums.
If you look at history from a few years back, perhaps even on this site, you'll see that EBMM auctioned off an outrageous Spinal Tap guitar or three on eBay when the last Spinal Tap revival happened. I think Nigel/Chris played it at a few US shows, and they made a few models which they auctioned off for Sterling and Casey's kidney foundation.
As I recall, it was an insanely modified Albert Lee with 4 - yes FOUR! - humbucking pickups, a cool hotrod flame paintjob, and a gearshift trem complete with a pool ball shift handle - basically, think of a ZZ Top Model T mated with an AL, and you've got the idea. It was totally whacked out, but was really, really cool in a twisted way...just like The Almighty Tap.
My guess is there was a prior Jamie/Chris/Sterling relationship which carried over into the Freaky Friday movie. I do recall seeing a Fender Telecaster (the mahogany one with the DeArmond pickups - like an LP Junior) being used as part of the ad campaign as well, but as we all know they're the ubiquitous, iconic rock brand guitar. I'm glad to see that EBMM managed to at least get at least half credit in the branding on this one, and most of the press photos I've seen were the ones that had the Luke in them.
(Moderators, please fill in the rest of the blanks....I thought this was a great move on the company's part!)
Long live The Tap!