Like you I would think the "inclusions" would suggest it is not of sufficient quality to be Murano. Art glass in a similar style to Murano was made well in many other countries during the 1950's 1960's - USA, Czechoslovakia, Japan. These days it is (comparatively) poorly made in a myriad of places, most notably China and India. Neglect can make an item dirty very quickly, especially if stored in a garage or similar. You may be able to tell from the base - any art glass of a reasonable age will have light base scratching from being moved around. But again such scratching can easily be added to give the impression of age. I'm sure you know all this.
If you like it and want to keep it, what does it matter? If it is for sale, the I would suggest "murano style" is the most you would want to say - there are numerous listings on eBay Oz that list this way. Or just "red art glass centrepiece" - most people who want to buy decorative items look for colour. I imagine it would be very expensive to post - you may have another way of selling that does not involve postage.
