Sliding window lock with springs in recently purchased house.

Hi, We bought a house with all the window locks (except one) non functioning due to missing covers. I am not able to find any replacement covers. I am unable to find any window locks that that would work. I would be delighted if you had any ideas on where to find new covers or new locks! Thank you! Patti Sliding window lock with springs in recently purchased house. House built in 1969, but we think windows may have been replaced in 2007 fire.