Oshkosh B'Gosh Flannel Shirt Mens Med. Vtg Plaid Tan Blue Flannel Made in USA. Pre-Owned Excellent condition Smoke Free Home. This vintage Oshkosh B'Gosh flannel shirt is a classic piece for men in size medium. Made in the USA, the shirt features a beige and blue plaid pattern with a collared neckline and spread collar style. The button-up shirt is crafted from comfortable cotton flannel fabric, making it ideal for the winter and fall seasons. With easy care instructions, this casual shirt is accented with buttons and carries a subtle USA theme.