Your table was made in the late 1950's or early 1960's. By Spraque & Carleton.
This company was very prolific producing a large quantity of tables, chairs and small furniture items. They primarily used maple in their construction.
By the 1940's this company was producing large quantities of furniture, they were producing over a million rocking chairs a year as well as small furniture pieces and dining room sets.
I noticed that you have your table for sale at $800 but you also have some close-up pictures on the listing page.
Your table is quite a bit of damage to the top which means that it would need to be sanded and stained.
If in excellent condition your end table would sell for around $150 but in the present condition I would say it might sell at $50.
This furniture is well constructed and with proper care is still in use in numbers of homes around the country but I see Sprague and Carleton tables and chairs at auction all the time. I have seen quite a few of these triangular end tables.
As for rarity, this particular table is not rare.
