I would think the back straps alone would weigh close to 5 lbs each, never weighed them honestly, but hell, they are near 20- 24" long if you carve it out tip to stern.
How much meat did you get total? they may have inadvertently mis-labeled, or ground by mistake (trying to be positive, even though you likely got screwed)
“Never be afraid to try something new, or diy. Remember, amateurs built the Ark, professionals built the Titanic”
Friends don't let Friends drink and post.......
The first 5 day's after the weekend, are the hardest....