While doing some research on an unrelated crown matter, I stumbled across something in 1 of my old Rolex parts books that I think solves The Great Triplock - Crimped vs Solid - Mystery
You will notice that both the 703 & 704 have the same relief, which makes them, at least from their cap sides, indistinguishable from each other. However, Rolex added the designation, MONOBLOC, & displays the 704 (as well as the 604, 531 & 480 Twinlocks) with an all-green pic. Meanwhile, the 703 (& 603 & 530 Twinlocks) is pictured as having a yellow core with an outer green cap (which is no doubt secured or crimped around the inner core along its outer skirt).
I have viewed these pages many times, but for some reason never made the connection at any time during this controversy.
The bottom line is that Justasgood is correct that the 704 appears solid when viewed from its underside & the 703 is crimped. Otherwise, externally, they look the same. And unless anyone has any other new insights to add, I think we can consider another Rolex case closed.