• 1 Light TRS (209266, round coil) and 1 Heavy TRS (219441, square coil)
• 1 Heavy HS for USP/USPc/HK45 (214695, long spring) and 1 Heavy HS for HK45C (234460, short spring). Note that the shorter spring is for the HK45C only, not USPc.
A factory DAO would have all heavy springs (TRS/FPBS/HS). But a pre-owned DAO could have its factory spring(s) swapped out for lighter versions by previous owner.
First, the TRS. If you use the Heavy TRS and HS springs that come in the LEM kit, you will have a "somewhat" Heavy LEM. It all depends on which FPBS you currently have in your DAO. If you have a Heavy FPBS (as a factory DAO would come with), then you will have a Heavy LEM. If you have the V1 FPBS, then yours will have a bit lighter than Heavy LEM. You'll need to check your FPBS to be sure.
If you use the Light TRS with the Heavy HS from the kit, again, it depends on which FPBS you have.
The next spring is FPBS. A Light LEM uses either a V1 FPBS (214192) or a new-style Light FPBS (209296). You cannot use the new-style Light FBPS because yours is a KG and has the old-style FPB. Old-style FP/FPB uses old-style FPBS. So, you will need the old-style FPBS (aka V1 FPBS). Again, check your FPBS. You might already have the V1 FPBS.
And, finally, the HS. A light LEM uses the V1 HS (214300). A factory DAO would have a Heavy HS, which should be the same as the Heavy HS (214695) that comes in the LEM kit. Yours might have the Heavy HS or some other spring. Need to check that.
If you leave all factory DAO springs, you'll have similar pull weight to a Heavy LEM. I said factory because you could have a DAO that could have been modified with lighter spring(s) if it wasn't purchased new from factory.
What you could do is post a pic of your current TRS, a pic of FPBS, and another of your current HS and the longer, Heavy HS that comes with the LEM kit. That way we can tell what you have and what you will need.