No (short answer).

Dobro body shapes/outlines are unique.

The nomenclature is a tad confusing. The "E" & "R" designations are Beard's , referring to his large and "classic" body designs. There is/was also "E" & "R" (Incl Vintage R) models.

Tim Scheerhorn referred to his body designs as the "L" & "R".

In each case that refers ONLY to the top & back profiles and not to body depth or other design factors. The "R" profile is patterned after pre-war Regal built dobros. The "E"/"L" shapes (and others) are purely designed by the contemporary builders.

Confused yet? ;-)

h

They might come pretty close to equating  in a couple sizes only.

Did a quick measurement of some of my guitars that are not currently in their cases. Just measuring the width of the lower bout and the body depth, but again it was quick so not necessarily exact.

Clinesmith = 14.25"  Todd didn't assign his guitars additional specs like L-Body or E-Body, but they are very close to L-Body Scheerhorns and E Model Beards. He built only a few smaller body guitars.

1936 Dobro Model 37 (Regal-built) a hair over 14"    I was surprised that the vintage Dobro was that close in width to the Clinesmith. The most significant difference is the depth: 3.5" for the Dobro and 4" for the Clinesmith. That half inch contributes a lot more bass. It's also the same depth as a Scheerhorn L-Body, I don't know the width.

Martin dreadnought, easy to find online: lower bout width = 15 5/8"    Depth = 4 7/8"  

Martin 000   lower bout width 15".   Depth can vary depending on model. 4.1"  to 4 5/8"

Martin 00  width lower bout = 14 3/8"    Depth: 4 1/8" to 4 3/16"

I have a Yamaha FSX5 that is pretty much their equivalent of a 000-18  Width = 15"  Depth = 4 3/8"

I did find here in the archives that someone posted  measurements for his R-Body Scheerhorn: Width at lower bout = 14 1/4"      Depth = 3 3/4" So that was very close to my pre WWII Regal-built, hence the R-body

I later found while googling the L-Body 'horn:  Width = 15"      Depth = 4".           I was surprised to find that the width is showing 15" - that's a significant difference compared to my Clinesmith, 3/4" wider. But that was from ChatGPT, and I have found in our more obscure part of the guitar world - resophonic - ChatGPT is sometimes wrong.  Can someone check the width of their  L-Body and verify this measurement?

I'm going to stop there and not look up Beards,  need to climb my way out of this rabbit hole. 

In conclusion I think most squarenck reso guitars are pretty close to a Martin 00, and the larger ones - excluding the tubby looking old Sho-Bros that have never done a thing for me in either looks or sound, might be close to a 000. 

When players have been looking for cases for  squarenecks over the years and they don't want to pay the bucks to have one built, the usual recommendation using a flattop case has been for a 00 or occasionally a 000. A dreadnought case is definitely too large. Obviously, precise measurements should be made before placing the order. 

Thank you, very much. I know that was a but of work from both of you.

Tom Warner built Appalachians are “a size like an L body- wider waist and about 4'' deep” - per him.  The list goes on and on.