Date approximate?

https://preview.redd.it/r6n6q5xomebh1.jpg?width=2250&format=pjpg&auto=webp&s=ce1a1b3a4bc78f81e7236c2f8715f2e4c94f818d

https://preview.redd.it/zwxal5xomebh1.jpg?width=2250&format=pjpg&auto=webp&s=e84a643ab28c3dc918daa487b0740d2c4eaee255

https://preview.redd.it/1mr9isxomebh1.jpg?width=2250&format=pjpg&auto=webp&s=bd2d9fa705337d6cf0b8dbabe00d6212ded74f9f

https://preview.redd.it/7qpwdrxomebh1.jpg?width=2250&format=pjpg&auto=webp&s=a70e112b57c641900a7174eed3b15de7b71c6b38

https://preview.redd.it/05paxqxomebh1.jpg?width=2250&format=pjpg&auto=webp&s=c941bd1712c53f58ea753349a6dadd3ace06a87f

Is this a Field Master (the front zip pocket is unusual) and is it possible to date approximately. TIA