@Butnup. I’m glad that you found my comments helpful, this forum has been a great help to me and I like to put something back into it.
It’s interesting about the weight and the method you used, yours was better. I quickly placed the Uke vertical (with lower bout on the scale pan and side pressure to stop it falling) and used a thirty year old spring balance. Hence my first result was indicative and my method more quick than accurate - a first approximation. The re-test gives 14oz for KA-P with strap button and strap, so in-line with expectations from your KA-15S weight.
If one of your Dolphins is all wood then the edges of the back and sides will likely be square whereas the moulded ones are a little rounded. Taping the back will likely give a different sound too. I’d be tempted to look in the sound hole with a mirror to see whether all the inside is painted and whether there is a block at the base of the lower bout.
In addition to a decent set-up and fluorocarbon Strings I fit a bone saddle too to Dolphins that cross my path, I think that you will find that a worthwhile change. It would be interesting to do the same modifications to both your Makala’s and your KA-15S and then compare them, I suspect that the Kala will be slightly better.
For what it’s worth I’m a great supporter of Kala’s and Makala’s basic models; the Makala’s make good beaters and the Kala’s can be very practical instruments for the club player. Of course they won’t chime up the neck in the way some much much more expensive Ukes might (say eight and more times the price) but they take a lot of outgrowing and give wonderful value. Player skill is everything and after that it’s a case of what she or he can wring out of the instrument.
Weight’s an interesting guide and it might be helpful if manufacturers published details, but there is potential to mislead too. Heavy Ukes are typically overbuilt and that seems to make them ridged and hence vibrate less; light Ukes don’t have the same strength and so might break in use (rough handling, etc.) but they typically vibrate better. However weight is but an indicator as it’s where the weight is in the build that matters, well that’s my belief.
Edit. If for some reason you want to date your Makalas / Kalas then I believe that that is possible. The label within the instrument has a three or four digit number towards the lower right hand corner. IIRC the last two digits are the month and the others the year of manufacture.