I have the speakers I grew up with in the 50's 60's.

makes sense, thanks

The 375 is a large compression driver that is normally attached to a horn.  They were the largest such driver made by JBL in the time period you are writing about.  They are highly sought after  are sought after.  They were used in a number of Iconic period speakers like the Hartsfield and the Paragon.  There should also be a woofer extended range driver present, unless they were removed etc. 

they have never been opened  and are in tact as they went from mothers house to mine.There is  one area where the veneer has peeled off but that is cosmetic on only one. . My husband was offered $ for the horns but refused to open them       He was once involved with Erath speakers, a small houston based business in the late 70's.  .

I do not see a value in the bluebook- guess I am not looking hard enough

Jane- The problem you are having is likely a result of some semantic challenges.  The James Lansing 375 is a "driver" or individual speaker that covers a portion of the entire sound range.  It was used in professional theater type and PA type systems, as well as (less frequently I would imagine) in home applications.  As mentioned by mechans the active part (driver) usually was attached to some kind of horn or acoustic lens to project the sound.  In a home system like you apparently have, it would have been mounted in some kind of cabinet with the lens or horn inside (maybe visible from the outside, and there is probably a large low frequency driver or woofer also in that cabinet.  If you can post a link to a picture of the front and back of the speakers, you can get better information.  Given the age, and the variations in mounting and etc, you will not find a reliable bluebook value.   Also condition and location will affect value, since they are probably large, heavy cabinets and shipping will be expensive.  It will likely require an auction with very thorough pictures and documentation to establish a true value. Given that they are collector-type items, with a world-wide but limited appeal, you will probably want to reach the largest possible audience when you choose an auction site.