In short: Yes
Longer answer: Yes, but it depends.
Building a Wordpress site is trivial, writing themes isn't all that hard, there are of course some Wordpress functions and templating things that you should know about, but for the most part you can rely on the Wordpress Codex for that.
If you have a lot of custom data collection happening you could either write a Wordpress Plugin that does the same, or you could write them as a webservice, of course you could also keep them as standalone pages. I guess it all comes back to the "it depends".
If your site has a lot of content e.g. news articles, blog article etc., you could probably write an RSS feed or some such to import content in to Wordpress.
Like Retro said, it will probably also depend on how adept you are at WP