I've been doing crazy research and not getting a definite answer as to what will be a drop-in replacement . . . until this thread. Thank you!!
Here are my prior notes:
Email Gibson/Epi with a photo and serial number for specs on Coupe: service@gibson.com
As per a review on Musician's Friend: http://www.musiciansfriend.com/accessories/kluson-3-per-side-tuning-machines#productDetail "I replaced the stock tuners on my Epi Casino Coupe, and the new Kluson's look and sound great. Stay in tune exceptionally."
http://www.wdmusic.com/3_on_side_kluson_nickel.html
Kluson 3+3 nickel tuners fits 11/32nds Gibson & Martin Guitars SD9005MN
http://www.stewmac.com/Hardware_and_Parts/Tuning_Machines/Solid_Peghead_Guitar_Tuning_Machines/Gotoh_Vintage-style_Oval_Knob_3and3_Tuners.html. Gotoh Vintage-style Oval Knob 3+3 Tuners
Grover Deluxe Vintage #133N...drop in replacements for the stock tuners.
Check out Waverly specs and see if any of those match. They come with a lifetime warranty.