[We've moved this discussion from this thread on pie in San Francisco http://chowhound.chow.com/topics/904568 -- The Chowhound Team]
Don't overlook that after public-health data on trans-fatty acids became widespread in the 1990s, followed by a US food labeling requirement, food manufacturers have been eliminating the cheap hydrogenated cooking fats like Crisco (tm) -- some firms faster than others. My query at the Sunnyvale Marie Callendar's was easily 10 years ago and the fats used may have changed.
Of course, artisan specialty bakers, unlike the "industrial" ones, have long used more traditional fats, like butter. Many of the appealing pie-source references I've read on this board were to those. Pies seem to be another recurring thread topic here.