I've just had a yellow rose #73 with linerlock through the post. Really happy with it (thanks Derrick). Mine also has the exact same amount of underblading. I agree that it is probably part of the design. Forgive if I'm wrong but didn't the slipjoint and linerlock versions (#73) come before the backlock (#72)? In which case GEC would probably have used the same blade tang shape, simply adding a notch for the lockback spring. The tolerances are too fine on my knife for it to be sloppy work. If it was then the linerlock wouldn't work as it pinches the blade tang on the underside, behind it and locks it against the spring, effectively locking the blade on three sides. This makes for a very tight lockup (one of the things I'm pleased with). Yes I'd like the blade tang to be flush with the spring but it's not a deal breaker. I've gt this knife for a user and form that perspective it works just great 