No. All LG retail writers have DVD-RAM support. Having lightscribe does not make one model better than another. Some people don’t want lightscribe ability in their drives because lightscribe capable drives tend to be more expensive than non-lightscribe capable ones. So, I’ve noticed lightscribe and non-lightscribe models seem to be introduced as entirely different lines aimed at different groups of customers. So you really should not compare them with each other in that sense, because they are not designed to suit the same purpose.
The H10N is actually a newer model than the H20L. The H20L was released a few months before the H10N. Do not be deceived by the larger model number - it does not mean it is a newer model. LG seems to release their drives in order they choose, not necessarily according to model number.
Now if you do actually want to comapre the specifics of each drive (however unfairly) :
The H20L uses a different chipset (panasonic) from the H10N (renesas). They have quite different properties as a result. I won’t go into specifics, but the very way the burners write the same type of discs is entirely different. Both seem to have good burn quality though.
In terms of DVD-RAM writing, the H20L supports 5x DVD-RAM writing, whereas the H10N supports 12x DVD-RAM writing. The H20L supports 8x DVD+R DL writing but the H10N does this at 10x.
If you really want a fair comparison, you should match the H10L with the H20L. The H10L is the lightscribe equivalent of the H10N. From what we can tell so far, (this is a very new drive - it seems to be less than a month old or so) the H10L is identical to the H10N, except it has lightscribe support.