avodah zarah - Abram's worship of El Elyon

In Genesis 14:18-20 Abram recognizes the deity El Elyon of the Jebusite monarch Melchizedek.

Some scholars have investigated into the meaning of this name El Elyon and propose that it actually consists of two separate names of two deities. El being the son of Elyon.

According to Marvin Pope in his book "El in the Ugaritic texts".

Philo of Byblos identifies Elyon as being a separate deity who is the grandfather of the Ugaritic god El. He then goes on to compare Elyon to the 13th century BCE Hittite god Alalu.

https://books.google.com/books?id=ns4UAAAAIAAJ&pg=PA55&lpg=PA55&dq=elyon+in+ugarit&source=bl&ots=TNQkXWyGMW&sig=RlsjOctbw4rwdwkBQpsOzSpeQ4g&hl=en&sa=X&ei=goU4VZy0BcPAsAWEsIDADQ&ved=0CCQQ6AEwAw#v=onepage&q=elyon&f=false

Lastly, there is an Aramaic inscription known as the Sefire stele from 750 BCE that also uses the term El Elyon.

According to John Day:

The inscriptions may, under one possible interpretation, record the names of El and Elyon, "God, God Most High" possibly providing prima facie evidence for a distinction between the two deities first worshipped by the Jebusites in Jerusalem, and then elsewhere throughout the ancient Levant.

If this is indeed the case would that mean that Abram actually proclaimed his allegiance to numerous deities by accepting a blessing in the name of El (son of) Elyon?