Well, yeah, sort of.  But to use this method you would already have to 
know what the various configurations of depth adjustors looked like, 
for comparison.  In case of the "Craftsman" (Sears) plane I wrote 
about, it has a depth adjuster nut that is not brass, but "white 
metal."  I have another MF plane with the same general design of hollow 
adjuster nut, but it is brass.  On other MF planes, the brass adjuster 
nut is not hollow, but "filled."  That is, they vary.
	For MF (and planes they made for others), the lozenge-shaped 
depressions in the back of the frog seem to be consistent, through 
older and newer, black paint or red.
		Tom Holloway

On Friday, August 27, 2004, at 03:57  PM, Michele Minch wrote:
> T&J Holloway wrote:
>
>>  He passed on a tidbit for identifying planes with other brand names 
>> but made by Millers Falls.  The givaway is a lozenge-shaped 
>> depression, maybe 3/8" long, cast into the underside of the frog, on 
>> each side, close to the top.  If your Fulton, Craftsman, or other 
>> brandname plane has those dimples in the casting, the word it that it 
>> was made my Millers Falls.
>
> GG
> i think a quick ID is attained by looking at the brass depth adjuster 
> - Stanley, Sargent, and M-F all had distinctive shapes.
>
> Ed Minch