Based on your description and the photos, here is an evaluation of value. The Cashmore name is rated as Brand Value level three (BV3) by the market. The gun appears to be an Original Quality level seven (OQ7) gun. And, the appearance and description seem to fit Current Condition level 8, "Marginally shootable, significent repairs required soon or poor restoration."

BV3-OQ7-CC8 = $300. Note that this evaluation assumes the gun is safe to shoot.

Hope that helps.

DDA