(Just assume that both Abydos and Icarus still exist (planets and their stargates).)
Address of Abydos contains the Orion as the 6th symbol.
P4X-351 (Icarus base) has the Orion as the point of origin.
Does it mean that stargate on Icarus cannot dial Abydos ?
Here is my theory. When stargate is moved to different planet, its point of origin may change (from Earth to Orion). Any of the remaining 38 symbols may become the new point of origin. Then the previous point of origin symbol (Earth) must substitute the old symbol (Orion) that now serves as the new point of origin. So, when you try to dial Abydos from Icarus, then the 6th symbol is not Orion but Earth.