This style of pistol was made both by Beholla (Becker and Hollander) and and by August Menz (his used the trade name Menta during the First World War. After the war, Becker and Hollander stopped, but Menz kept on, and the Stenda Werke began making them. Barrel pins from the other two companies might be interchangeable with your gun.
After making guns just like yours, Stenda and maybe Menz changed the design and got rid of the barrel pin. Stenda used a spring latch (I have one of that type). Menz may have used a rotating catch. Oh, and a man named Gering got hold of a lot of parts, and assembled guns like yours under the trade name Leonhardt. All names to watch for if you are looking a part.