Are SME IPO shares allotted on first come first serve basis?

No, allocations of shares to applicants in an IPO do not depend on a first come first serve basis rather it works on how the IPO gets investors' response. If an SME receives a full-subscription or under-subscription (Applications received are equal to or less than the shares offered), then all the investors will get a full allotment of shares they have bid for. Unlike it, in case of over-subscription (Application received exceeds the number of shares offered), then allotment to retail investors will be done on a computerized draw process.