130F is fine provided your equipment is accurate. Pasteurisation takes place as low as 126F but this wouldn't leave much of a safety buffer.
Cooking by sous vide, actually cooking by any method, relies on heat penetration. This is impacted by thickness, not weight. You have not at any stage told us how thick your roast was. But after 6 hours, it is unlikely that it would be undercooked, ie at a lower temperature than the waterbath. More likely that it was less done (or more pink) than you expected. This is likely around the bones, which form a heat shield.