Vintage National ? Double Neck Lap Steel Guitar Lucite FRETBOARD

Description

This was purchased from an estate that had a National, double-necked lap steel guitar and therefore I am assuming that it fits that brand but am unsure. It appears to be a true vintage part but I am no expert.
The photos show the dimensions and also the measurements for the mounting holes (last 4).
There normal wear from use and age along with a common crack on the bottom where the mounting screw was overtightened but the crack isn't all the way across.
If I am wrong about what this fits, please let me know!
Feel free to ask questions before bidding or purchasing.
Please see photos closely for details.
* Florida residents are subject to a 7% sales tax.
SOLD AS IS. FREE SHIPPING TO THE CONTINENTAL UNITED STATES.
* I am a small business and do my best to picture and describe items accurately, but sometimes, I make mistakes. If you purchased an item and believe that I have made a mistake, please contact me. Good communication is the best way to resolve any issue.
* If the item does not arrive in the estimated amount of time, please be patient and contact me. Due to the impact of Corona, shipping times have been taking longer on some items.
Thank you!