You are correct as it is a Small-eyed Snake. As pointed out, no red or pink on the lower laterals and the mid-belly should be cream or much lighter pink than the edges of the ventral scales. The black marking down the centre of the belly does not occur on RBB. There is no evidence of pale brown on the tip of the snout and under magnification you see than the eye is very small (in contrast to the large eye of a RBB). As suggested check the anal scale. Also, it will have all single caudal scales while RBBs start off single and then become divided.
Small-eyed snakes to a metre plus in size are not uncommon – or at least didn’t used to be (many years ago). It is easy to initially confuse the two when you have such a strong reddish-pink ventral colour. The lack of pigment along the lower flanks, the slimmer build (RBB are more robust for the same length) and the small eye and narrow head all come together to make it fairly easy to distinguish at a glance once you have had some experience with both.
Even though it is dead, do be careful of the bitey end as it may still contain viable venom.
Blue