Question about Blog Posts Index

I have a question about using a Blog Posts Index as a homepage.

If you have set up your wordpress site to show full blogposts on your homepage by default is there a way to know this via the source code of the homepage? For example, if I were to be searching the web for wordpress blogs where the full blog posts were on the homepage vs blog excerpts, blog post links, etc. would I be able to distinguish from the source code?

Thanks in advance.