I'm not the first to say "No", but I want to actually show where ～たら comes from, if it's not an abbreviated form of ～てから. Consider it a proof of sorts. :)
The Classical Japanese of early Heian period had a form called ～たり form, which was used for several jobs that today are fulfilled by the ～た, ～て and (the modern) ～たり forms. This form was attached to the renyōkei (連用形), which is the verb stem that ends in I for Godan verbs (this is the stem to which you attach the ～ます or ～たい endings).
The ~たり form was later shortened to ~た in speech and became the past form we all known and love today, but before that, it was actually used to build a few other forms. Now, the ～たり form was actually creating a new verb (just like adding the potential, passive or causative endings to a verb today create a new verb), so it had it's own stem to which other endings could be attached. One of them was the old hypothetical ending ～ば (actually, the famous particle は which became ば after the verb). ば was attached to the mizenkei (未然形), which is the verb stem that ends in A for Godan verbs (this is the stem to which you attach the ～ない ending used for negation). Since, the mizenkei of ～たり was naturally ～たら, the whole thing together was ～たらば, which at sometime became a very common complex form for conditionals. e.g. (I invented this up myself, so it's probably not quite authentic):
書きたらば、死ぬ。 If you write, you die.
In modern Japanese, the classical ～ば form became the modern conditional ～ば which is now attached to the E stem (已然形 izenkei), and is much better known as the -eba conditional ending. But what happened to the complex ～たらば～ form? It was shortened to ~たら, but also started using the different base that ～て and ～た forms (the later also a shortened form of ～たり) were using. In Ichidan verbs (such as 見る or 食べる) this is still the same as good old renyōkei, but in godan verb, a few changes occured:
- wakari + tara -> wakar + tara -> wakat + tara -> wakattara
- kaki + tara -> kai + tara -> kaitara
- oyogi + tara -> oyoi + (voice) + tara -> oyoi + dara -> oyoidara
- mati + tara -> mat + tara -> mattara
There are more, but that's the gist of it.