Has anyone actually seen a Steinway grand with a plate, never
repainted, stamped within the "V" along with the serial number, "Style
LR Duo-Art"? I never have. But then I've never seen a Steinway "M"
with the Duo-Art version designated Style M or MR. They've all been
labeled "Style X" or "XR." It has always been my assumption that,
after Steinway started shipping extended-case "L" grands to Aeolian for
installation of the Duo-Art, these, being the same length as the "O,"
continued to be rubber-stamped "Style OR Duo-Art" by Aeolian.
If you have a 6'5" Steinway Duo-Art grand, it's fairly easy to tell
whether the piano is an "O" or an "L." On the "O," the rear
circumference is in the shape of a near-perfect semicircle. With the
"L", the curvature on the left side (viewed from the keyboard end) is
much sharper than on the right, allowing for an increased soundboard
area. Years earlier, the same change was made in the slightly longer
Steinway "A," resulting in the "A2." With the introduction of the "L,"
the "A2" was lengthened just over three inches to more appropriately
fill the gap between the "L" and "B" grands. The lengthened "A" became
known as the "A3." Both "A2" and "A3"
grands were built with extended cases to accommodate the Duo-Art.
Their lengths are 6'8" and 6'11.25".
I don't know precisely when all these changes occurred. I have
requested this information from a friend at Steinway, but don't know
how soon he will respond.