If the case is not stamped with the manufacture, there's a good chance your not going to know for sure. Major manufactures stamped their leather, if where the stamp was is missing it MIGHT be identified by sight.
WWII vintage
The Value is determined by the current condition and age of the rifle. There are about 17 different versions of the model 25. Next to the Red Ryder it's one of the most produced air rifles by Daisy. With out seeing the rifle it's hard to determine the age or condition and setting the value is not possible.
Gamo never made a Sniper model rifle. It depends on the model, each one is different. You need to locate the model number and ask your question again.
By the serial number on the rifle.
With 90% blue and normal wear for a rifle of this vintage: $350-$400. In 98-99% condition: $700.00
By the serial number on your rifle.
No way to determine without knowing manufacturer and model of rifle.
Hard to say without the serial number to age the rifle,and the overall condition to determine the value of the rifle.
A Winchester model 1894 produced in 1901 can range in price from 350-2,000 dollars depending on the overall condition of your rifle,and any special features that could have been ordered at the time of production.I would choose to have a rifle of this vintage apprasied by a Winchester collectors assoc.member or a well respected gun collector to establish a price for your vintage Winchester model 1894.This model has quite a bit of collector value.
By adding the serial number to your question.
Will need a serial number from the rifle to determine the age.
This model Cross references over to a Mossberg model 42 or 42A extractors can be purchased at http://www.wisnersinc.com/rifles/mossberg/mossBArf.htm for around $12, Vintage Mossberg .22 rifle information can be found at home.epix.net/~damguy