I figure by the time I have this bike kitted out for some real distance rides, every ounce is gonna count.
Only my opinion, but . . . I think the difference in weight between one set or another of guards might be inconsequential.
The KLR650 holds about 6 gallons of gasoline, men say. This fuel weighs about 6 pounds per gallon. In the course of your travel, you will have a weight variance of 36 pounds, if you top off the tank and run it dry.
(One aspect of the weighting of the bike; the fuel load is centered ABOVE the bike's center-of-gravity, producing some discernible FULL/EMPTY differences in handling modes; the guards are located well BELOW the center-of-gravity, with less effect on handling.)
Various stock weights have been quoted; Kawasaki says the "curb weight" is 432 pounds (don't trust their specifications entirely; they say the ignition is CDI (it's not, on Generation 2s) and the rear brake is single-piston caliper (it's actually twin-piston, on Generation 2s) http://www.kawasaki.com/products/pro...ns.aspx?id=702
Regardless, taking 'em at their word, the fuel weight will vary by 8 % of the bike's stated curb weight. If the nerfs vary by, say, 5 pounds (a high estimate, I'd think), we're looking at about 1 % of the total heft, within an unavoidable swing of 8 % from fuel consumption and replenishment.
Still, it's YOUR bike; if your weight budget is critical and sensitive enough to you, by all means choose the lighter accessory, even if you otherwise prefer the design of the heavier one.
A consideration: The stock plastic bash plate appears lighter than any aluminum one; which will you choose? Again, I support you in whatever decision you make; only you know your own requirements and preferences; only you need to be satisfied by your choices.
Your detailed planning on outfitting your bike will doubtless help assure enjoyable and safe travel, bon voyage