There are no year tags on this jersey but Mike was a rookie with the Vikings in 1976 which corresponds with the MEARS dating of this tag (1972-76, the medal no longer appearing on most 1977 shirts). Getty image confirms the style of fonts, sleeves and front/back (images and numbers included). The jersey was manufactured by Sand Knit and has the team exclusive tag. The shirt is tagged a size50 and Hamilton appears on a nameplate on back. He has autographed the jersey on the front number.
The jersey exhibits heavy game use with team repairs on the shoulders and sleeve along with evident wear on the uniform numbers (#61), especially the back numbers and several small holes/tears on both shoulders. The left sleeve has been altered in that it shows it least two hem marks that make the left sleeve tighter. The shirt is all original as issued with no signs of any restorations and remains as a stunning example of what a game worn football jersey of a guard should look like.
As for Hamilton, his career spanned from 1976-1984 as an offensive linemen all of which were played in Minnesota.