I guess there's only one way to find out.
Variegation is kind of unstable with many succulents, especially the ones in that family. So it can come and go unexpectedly, increase or decrease in unpredictable ways. Generally the trend is toward normal growth and away from the variegation that we like so much, but you will also occasionally see a branch that totally lacks chlorophyll. These will die if separated from the mother plant because they are unable to make their own energy.
My suggestion is to constantly be selecting for the variegation you like. So if a leaf propagation turns out normal, toss it (or better yet give it to somebody who would appreciate it). There is a chance it will change later in life but it's not high. You will probably see the best odds for getting what you want by propagating stem cuttings (like the one that worked out well for you) instead of leaves. When variegation seems to be particularly unstable (coming and going even on the mother plant) I sometimes take a branch and start a backup plant, just to have something to fall back upon if the mother plant turns all green.
Experience is probably the best teacher here, these are just my usual strategies for variegated plants.
I guess it's good to remember that almost all variegated succulents started out as normal all-green plants. Then at some point likely in a big nursery one plant looked different and somebody decided to make more of it. The spontaneous appearance of variegation (a low probability event) is hard to predict and in most cases tends to be pretty unstable (returning to the wild type, which is going to be stronger and faster anyway). Instability is the cause of variegation and also the cause of reversion, two sides of the same coin. The variegates that are more stable tend to be more widespread in cultivation.
